Apparatus for detecting and capturing defective articles

ABSTRACT

A restriction die for detecting and capturing imperfect filters is carried in a pneumatic tube conveying line. The die has a bore which tapers inwardly from each end to produce a convergentdivergent passage having a restrictive orifice at its midpoint. A series of circumferentially spaced grooves extending radially outward from the bore are formed in the die so that the bottom surfaces of the grooves form an outline of a cylinder which is slightly larger than the entrance and exit diameters of the bore and which is concentric with the bore at any cross-section through the die. The grooves permit the conveying air to by-pass any blockage which may occur in the bore. Detector means is provided to indicate when a blockage has occurred.

United States Patent [191 Spencer Jan. 15, R974 APPARATUS FOR DETECTING AND CAPTURING DEFECTIVE ARTICLES [73] Assignee: R. J. Reynolds Tobacco Company,

Winston-Salem, NC.

22 Filed: Feb. 14, 1973 21 Appl. No.: 332,473

TO CIGARETTE MAKER 3,276,580 lO/l966 Horn et al 209/85 Primary EXQIZIZICT AlICH N. Knowles Attorney Grover M. Myers & Manford R. Haxton [57] ABSTRACT A restriction die for detecting and capturing imperfect filters is carried in a pneumatic tube conveying line. The die has a bore which tapers inwardly from each end to produce a convergent-divergent passage having a restrictive orifice at its midpoint. 'A'sfiskTcfr'cmfiferentially spaced grooves extending radially outward from the bore are formed in the die so that the bottom surfaces of the grooves form an outline of a cylinder which is slightly larger than the entrance and exit diameters of the bore and which is concentric with the bore at any cross-section through the die. The grooves permit the conveying air to by-pass any blockage which may occur in the bore. Detector means is provided to indicate when a blockage has occurred.

12 Claims, 6 Drawing Figures PATENT Ell 3.785.487

saw 1 [1F 4 To UGARETTE MAKER PATENTEBJAN 1 521174 SHEU 2 BF Q APPARATUS FOR DETECTING AND CAPTURING DEFECTIVE ARTICLES BACKGROUND OF THE INVENTION This invention relates to a restriction device for detecting and capturing defective articles and more particularly filter rods as they emerge from a filter making machine so that the imperfect filter rods will not cause blockages in the pneumatic transfer lines between the restriction devices at the filter making machines and a cigarette making machine.

When manufacturing filter cigarettes, generally, two types of machines are used. First, a filter making machine is used to form a continuous tow material into filter rods which are, in turn, placed in a cigarette making machine which joins the filter rods and a tobacco rod together to form the cigarette. in the past, the filter maker placed the filter rods in trays which were carried on carts or by conveyor from the filter maker to the cigarette maker where the trays were placed on the cigarette maker where the filter rods could be fed into the hopper of the cigarette maker.

It is necessary to maintain the filter making machines in a separate area from the cigarette makers to prevent contamination of the tow material from which the filters are made. This contamination is due primarily to the dust created by the cigarette makers. At various plants, the filter makers are located as much as 1,000 feet away from the cigarette makers and sometimes the filter makers are located on a lower level while the cig arette maker is located several floors above. As can be seen, the dispersed location of the machines necessitates the manual carry of the trays from one area to another in carts or the expense of an elaborate conveyor system for picking up the trays and transporting them to the various locations. Since labor costs have increased substantially in recent years and the use of trays is extremely slow, especially with the new generation of high speed cigarette makers, it has been necessary for the industry to develop new techniques for conveying the filter rods from the filter making machines to the cigarette making machines.

One of the more recent developments has been the pneumatic transmitter unit manufactured by the American Machineand Foundry (AMP). The AMF transmitter unit will pneumatically convey the filter rods from the filter making machine to the cigarette maker hopper. The AMF transmitter has a receiving hopper which receives the filter rods from two filter making machines. The filter rods pass through the hopper and are fed mechanically into a transmitting tube which picks up the filter rod and conveys it pneumatically through a steel tube to the hopper of the cigarette maker. Generally, there are ten transmitting tubes per transmitter unit and each transmitting tube feeds a single cigarette maker.

With the development of this pneumatic transmitter system, one of the major problems which has developed is caused by imperfect filters being transmitted through the lines of the system and blocking the tubes. The imperfect filters are produced for any one of several reasons which include wrinkles in the outside surface of the filter rod caused by the compression forces imposed on the filter rods when the feed wheels fail to align properly to feed the filter rods straight into the orifice of the transmitting tube, ruptured or enlarged diameter filter rods created when the air from the conveying jets in the transmitter hit the filter rods or defective filter rods coming from the filter making machine which are not located and removed during a visual inspection. The blockages may occur at any point along the line and it can be easily understood, if the machines are located remotely to one another as described above, it would be difficult to ascertain exactly where the blockage has occurred and eliminate it.

When using the AMP transmitter unit without the present invention, the procedure for eliminating a blockage is as follows. First, if the line is blocked beyond the transmitter, the cigarette making machine operator is notified so that the cigarette maker can be shut down. The conveying line is taken apart at the transmitter and high-pressure air is introduced into the line in the direction of flow of the filter rods. If this does not clear the line, the second procedure is to disconnect theline at the cigarette maker and introduce high-pressure air in the line in a back-flow direction from the cigarette maker to the filter maker. If this procedure is unsuccessful, the blockage has to be located by walking the line and visually inspecting through sight glasses located at intervals along the line. As mentioned above, these lines often run at an elevated position making if diffocult to get to them for inspection and service. When the blockage is located, the blocked section of the line is removed and taken apart and blown out with air or rodded out and reassembled. The remaining portion of the line is exhausted so that the filters that are backed up in the line may be removed.

From the above, it should be apparent that a single blockage can result in an enormous loss in cigarette production time and material waste as well as increasing the cigarette maker and filter maker downtime and increasing labor costs which increase cost per unit. Furthermore, without an initial inspection system for the filter rod, imperfect filter rods must be detected and rejected at a later part of production which further adds to the cost per unit. Thus, the present restrictordetector system will not only reduce the cost per unit, but it will increase the quality of the finished product.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a fully automatic method of early detection of imperfect filter rods.

Another object of this invention is to provide a device which will control the point at which a blockage will occur in the pneumatic conveying line of a transmitter 'unit.

Another object of this invention is to provide a simple and fast system of clearing a blockage in pneumatic conveying lines between the filter making machine and the cigarette making machine.

Still another object of this invention is to provide a system in which the conveying air will by-pass a blockage in the conveying line so that the remaining filter rods in the line may be transmitted through the line prior to shut-down of the cigarette maker, thus, preventing damage to the remaining filter rods from having to be put in motion while in the conveying line after the transmitter unit is restarted.

Still another object of this invention is to provide a restriction-detector device which will have a means of indicating to the machine operator when a blockage has occurred.

These and other objects are accomplished by the present invention through the use of a restriction die which will detect and capture imperfect filter rods as they are pneumatically conveyed therethrough. The restriction die includes upper and lower plates which have contacting surfaces. The plates are hinged securely together at one side, thus, permitting the restriction die to be opened. Along the contacting surfaces of the plates are channels having a generally semicircular cross-section. The channels are aligned with one another to form a circular bore when the die is closed. The bore tapers inwardly from each end of the die to produce a convergent-divergent passage having a restrictive orifice formed at approximately the midpoint of the bore. A series of spline grooves are formed within the plate so that the bottom surfaces of the grooves form the outline of a cylinder which is slightly larger than the entrance and exit diameters of the bore and which is concentric with the bore at any crosssection through the die. The spline grooves permit the conveying air to by-pass any blockage which may occur in the bore. Detector means is provided to indicate when a blockage has occurred in the restriction die.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and additional objects, features and advantages of the invention will be apparent to those skilled in the art from the following detailed description ofa preferred embodiment, taken with the accompanying drawings, in which:

FIG. 1 is a perspective of a restrictive die according to the present invention;

FIG. 2 is an elevation view showing a restriction die connected to an AMF transmitter unit, a portion of the restriction die is cut away to expose a convergent divergent bore;

FIG. 3 is a cross-section view at the entrance end of the restriction die taken along line 3-3 of FIG. 2;

FIG. 4 is a cross-section view of the restriction die showing the convergent-divergent passage taken along line 4-4 of FIG. 3;

FIG. 5 is a cross-section view showing the restrictive orifice at the midpoint of the restriction die taken along line 55 of FIG. 2; and

FIG. 6 is an exploded detail perspective of the restriction die according to the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring more particularly to the drawings in FIGS. 1 and 2, the numeral 10 indicates a restriction die unit which is connected through an in-put conduit 12 to an AMF transmitter unit 14 and through an out-put conduit 16 to a cigarette making machine (not shown). The AMF transmitter unit operates in the following manner. The filter rods 18 being supplied from a filter making machine are fed into the transmitter unit hopper 20 and are, in turn, fed by a mechanical pick-up unit 22 into a pneumatic transmitter unit 24. The mechanical pick-up unit 22 has two reciprocating feed rollers 26 and a driven vacuum wheel 27 which receive the filter rods from the hopper one at a time and insert the filter rods between driven upper and lower feed wheels 28 and 30, respectively. The vacuum wheel 27 has a series of vacuum passages 31 extending from its center, which is connected to a vacuum source, to apertures in the peripheral edge of the wheel. The vacuum in the wheel is used to hold the filter rods as they are inserted between the feed wheels. The feed wheels 28 and 30 insert the filter rods into the pneumatic transmitter unit 24 which includes a pneumatic chamber 32 and a nozzle assembly 34. The nozzle assembly 34 has three peripheral grooves 36 formed in its out side surface. A plurality of air jets 38 extend through the forward face of the V-shaped grooves and comm unicate with the central bore 40 of the nozzle. The conveying air, which is approximately 5 psig., enters chamber 32 through an inlet passage 42. The conveying air is jetted through the jets 38 into the central bore 40 and picks up the filter rods as they are pushed through the central bore 40 by the feed wheels 28 and 30. The filter rods pass through the input conduit 12 through the restriction die unit 10, then through the out-put conduit 16 to the cigarette maker hopper. The restrictive die unit for the present invention is used to detect and capture imperfect or defective filter rods before they are transmitted to the cigarett making machine.

The restrictor die unit 10 includes an upper and lower plate 44 and 46, resepectively, (See FIGS. 1 and 6) which are secured together along one side by a standard hinge 48 which is secured to the plates by a plurality of screws 50. The upper and lower plates 44 and 46 have a generally semi-circular channel 52 and 54, respectively, formed in their contacting surfaces 56 and 58. The channels 52 and 54 are tapered and will form a convergent-divergent bore or passage 60 (See FIGS. 3 and 4) through die unit l0 when the surfaces 56 and 58 are in contact.

As can be seen in FIG. 4, the bore 60 is tapered from each end of the die inwardly to produce the convergent-divergent configuration. The converging portion 62 of the passage begins at the entrance end of the die while the divergent portion 64 of the passage begins at approximately the midpoint of the passage and extends to the exit end of the die.

At the midpoint of the convergent-divergent passage is a restrictive zone or orifice 66 which has a diameter of approximately the same size as a perfectly-formed filter rod. The entrance diameter 68 and the exit diameter 70 of the passage 60 are approximately the same as the diameter of the conveying lines 12 and 16 which are greater than the diameter of a filter rod. Since the conveying conduits are larger than the filter rods, the filter rods may flutter in the conduits. The purpose of the convergent portion 62 of the die passage is to eliminate the fluttering motion of the filter rods as they pass into the restrictive zone or orifice so that the filter will pass through the orifice more easily. As the filter rods leave the restrictive zone, they are allowed to resume their normal motion in the divergent portion of the die passage.

It would also be noted that a plurality of spline grooves 72 are formed in the plates extending radially outward from the axis of the bore (See FIGS. 3 and 5). The bottom surfaces of the grooves form the outline of a cylinder which is slightly larger than the entrance and exit diameters of the convergent-divergent bore and which is concentric with the bore at any crosssection through the die. The diameter of the cylinder remains constant throughout the die; therefore, the

grooves will be shallow at the entrance and exit ends of the die while they will increase substantially at the restrictive orifice of the die due to the tapering of the bore. The purpose of the grooves is to permit the conveying air to by-pass the restrictive zone in the event a defective filter is captured therein.

As the AMP transmitter unit is operating, the filter rods are passing through the restrictive die at a rate of approximately 1,000 rods per minute; thus, it can be seen that, if a defective rod were captured at the orifice and no means were provided to permit the air to by-pass the blockage, a back pressure would build up in the system. The by-pass grooves 72, however, permit the conveying air to by-pass the blockage to prevent any back pressure build up in the system. Furthermore, the filter rods which proceeded the blockage will be conveyed to the cigarette making machine before the AMP transmitter unit is deactivated as will be explained hereinafter.

In this preferred embodiment, the upper and lower plates 44 and 46 are made from brass because of its easy tooling properties; however, the surfaces defining the bore are chrome-plated to increase the wear resistance of the die. It should be understood that any materials can be used to form the die, but one extremely important property to bev considered is the materials resistance to wear. "W

End blocks 76 and 78 have tubular portions 80 and 82 which extend inwardly into the die and are positioned in semi-circular grooves 84 formed in each of the upper and lower plates. The tubular portions are aligned axially with the convergent-divergent bore. On each tubular portion 80 and 82 is an O-ring 86 and 88, respectively, which produces an air-tight seal between the end blocks and plates when the plates are closed. The end blocks are secured to the lower plate 46 by screws 90. Extending longitudinally along opposite sides of the channel 54 (See FIG. 6) in the lower plate 46 are grooves 92 which carry sealing members 94. The latching clamp 96 is provided to hold the upper and lower plates together when the die unit is in use.

Secured to the upper and lower surfaces of the entrance block 76 are sensor support plates 98 and 100. The support plates carry tubular holders 102 and 104. The center of the apertures of the holders are aligned with the axis of the bore through the die and end plate 76. Holder 102 and 104 carry a sensor or detecting system 105 which includes a light source 106 and a sensing device 108, such as a photoelectric cell.

The in-put conduit 12 is secured to the entrance end block 76 and carries a sight glass 110 which permits the light beam from light source 106 to pass through the conduit to activate the sensing device 108. The light source and sensing unit are connected through wires 11]. and 112, respectively, to a signal amplifier 113 which is, in turn, connected through wire 114 to the existing AMP transmitter control circuit 115 in control box 116.

The sensing device 108 will produce a signal as long as the light source is not completely blocked; thus, the feed mechanism for the transmitter unit is timed so that the spaces between the filter rods being transmitted through the conduit are of sufficient duration to keep the sensing device activated. When a blockage occurs in the restrictive die and filter is captured, the filter rods back up in the die unit and the conduit so that a filter rod will obstruct the light beam passing through sight glass 110. When this occurs, no signal is generated and the transmitter unit will deactivate.

The detecting system of this preferred embodiment is connected in parallel with the automatic feed control circuitry linking the cigarette making machine and the AMP transmitter unit.

The operation of the AMF transmitter unit is controlled by the level of the filter rods in the hopper of the cigarette making machine. Generally, the AMP transmitter control circuitry operates in the following manner. A limit switch carried on the hopper of the cigarette making machine senses the level of the filter rods in the hopper and transmits a signal to the AMP transmitter unit control. When the hopper is filled to an upper limit of the switch, the switch is opened and no signal is transmitted. As the signal terminates, the mechanical pick-up unit 22 of the transmitter is deactivated; however, a time-delay circuit in the control sys tem permits the pneumatic transmitter unit 24 to continue to function for a predetermined time which is sufficient to permit the remaining filter rods in the conduit to travel to the hopper on the cigarette making machine before deactivation of the pneumatic system. After this time-delay, the pneumatic unit s deactivated also.

As the level in the hopper decreases, the limit switch is closed at its lower limit and the signal is again generated and transmitted to the control circuit of the AMP transmitter unit. The signal will immediately activate the pneumatic transmitter unit 24 to begin pressurizing the system, but a signal to the mechanical pick-up unit 22 passes through a time-delay circuit. After a predetermined time, the mechanical system is activated and the AMP transmitter unit begins supplying the cigarette making machine hopper.

As mentioned above, the detection system 105 of the present system is connected in parallel with the control circuitry for the AMF transmitter unit. Therefore, if a blockage occurs, the same sequence of events will occur to deactivate the system. When the blockage has been cleared from the restrictive die, the operator of the machine will remove the filter in the sight glass blocking the light beam and the system will become activated in the same sequence as described hereinabove.

Indicator lamps can be provided to give the operator visual indication of the shut-down and re-start of the unit.

It can be seen from the above description and drawings that the present restrictive die provides a fully automatic way to detect defective filters and control the point of blockage in a pneumatic conveying line. The device also provides a simple and fast system for clearing the blockage as well as providing the means for bypassing the blockage so that the remaining filters in the line may continue to the cigarette making machines prior to automatic deactivation of the system.

The above described embodiment can be modified in numerous ways; for example, other types of sensing or detecting means can be used to determine a stoppage, materials used for making the die can be varied, a shape and number of by-pass passages may be varied; however, these and other variations and changes can be made in the invention as above described and illustrated without departing from the true spirit and scope thereof as defined in the following claims.

I claim:

1. An apparatus for detecting and capturing defective articles being conveyed through a line by fluid, comprising:

a. die means having a restrictive zone therein for permitting properly formed articles to pass therethrough and capturing defective articles, said die means being carried in said conveying line;

b. by-pass means within said die means for allowing the conveying fluid to by-pass said captured defective article; and

c. means for permitting the removal of said captured ilcicclivc article from said die means.

2. 'l he apparatus of'claim I, further including means for sensing the presence of a captured defective article.

3. The apparatus of claim 1, wherein said means to permit said captured defective article to be removed includes:

a. first and second plates forming said die means, a

portion of a restrictive zone being formed in said first member and the remaining portion of said restrictive zone being formed in said second member; and

b. clamping means for holding said first and second members together and permitting said first and second members to be disassembled to remove a captured defective article.

4. The apparatus of claim 2, wherein said bypass means include a plurality of passages formed in said die means communicating with said restrictive zone to permit the conveying fluid to by-pass the restrictive zone when a defective article is captured therein.

5. An apparatus of claim 2, wherein said means for sensing the presence of a captured defective article includes:

a. a transparent portion of said conveying line located adjacent to the entrance end of said die means;

b. means for sensing the presence of a stationary article in said transparent portions; and

c. circuit means connected to said sensing means for de-activating an article transmitter.

6. An apparatus for detecting and capturing defective articles being conveyed through line by a fluid, comprising:

a. die means carried in said conveying line, said die means having a convergent-divergent bore with a restrictive orifice at approximately the mid-point of said bore, said die means permitting properly formed articles to pass therethrough and capturing defective articles; and

b. means for permitting said captured defective articles to be removed from said die means.

7. The apparatus of claim 6, further including means for sensing the presence of captured defective article.

8. The apparatus of claim 6, wherein said means for permitting said captured defective article to be removed includes:

a. first and second plates forming said die member.

a portion of said convergent-divergent passage being formed in said first member and the remaining portion of said convergent-divergent passage being formed in said second member; and

b. clamping means for holding said first and second members together and permitting said first and second members to be disassembled to remove a captured defective article.

9. The apparatus of Claim 7, wherein said means for sensing the presence ofa captured defective article includes:

a. a transparent portion of said conveying line located adjacent to the entrance end of said die means;

b. means for sensing the presence ofa stationary article in said transparent portion; and

c. circuit means connected to said sensing means for deactivating and reactivating an article transmitter.

10. The apparatus of claim 6, further including bypass means in said die means for allowing the conveying fluid to by-pass said captured defective article.

11. The apparatus of claim 10, wherein the said bypass means includes the plurality of grooves extending radially outward from said convergent-divergent bore, the bottom surface of said grooves forming the outline of a cylinder which is slightly larger than the entrance and exit diameter of said convergent-divergent bore and which is concentric with the bore at any crosssection through said die member.

12. The apparatus of claim 11, wherein said means for permitting said captured defective articles to be removed include:

a. first and second plates forming said die member,

a portion of said convergent-divergent bore being formed in said first member and the remaining portion of said convergent-divergent bore being formed in said second member; and

b. clamping means for holding said first and second members together and pennitting said first and second members to be disassembled to remove a captured defective article.

CUNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,785 ,487 Dated January 15 1974- Inventofls) Gilbert W. Spencer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 4 preamble, line 34, change "2" to --l--.

Claim 6 preamble, line 45, after "through" insert --a--.

Signed and sealed this 23rd day of April 191 14.

(SEAL) Attest:

EDWARD II.FLETCHER,JR. c. MARSHALL DAMN Attes'ting Officer Commissioner of Patents FORM PO-1050 (Hi-69k USCOMM-DC 60876-P69 u.sr GOVERNMENT PRINTING OFFICE: I969 o-aee-ssa, 

1. An apparatus for detecting and capturing defective articles being conveyed through a line by fluid, comprising: a. die means having a restrictive zone therein for permitting properly formed articles to pass therethrough and capturing defective articles, said die means being carried in said conveying line; b. by-pass means within said die means for allowing the conveying fluid to by-pass said captured defective article; and c. means for permitting the removal of said captured defective article from said die means.
 2. The apparatus of claim 1, further including means for sensing the presence of a captured defective article.
 3. The apparatus of claim 1, wherein said means to permit said captured defective article to be removed includes: a. first and second plates forming said die means, a portion of a restrictive zone being formed in said first member and the remaining portion of said restrictive zone being formed in said second member; and b. clamping means for holding said first and second members together and permitting said first and second members to be disassembled to remove a captured defective article.
 4. The apparatus of claim 2, wherein said by-pass means include a plurality of passages formed in said die means communicating with said restrictive zone to permit the conveying fluid to by-pass the restrictive zone when a defective article is captured therein.
 5. An apparatus of claim 2, wherein said means for sensing the presence of a captured defective article includes: a. a transparent portion of said conveying line located adjacent to the entrance end of said die means; b. means for sensing the presence of a stationary article in said transparent portions; and c. circuit means connected to said sensing means for de-activating an article transmitter.
 6. An apparatus for detecting and capturing defective articles being conveyed through a line by a fluid, comprising: a. die means carried in said conveying line, said die means having a convergent-divergent bore with a restrictive orifice at approximately the mid-point of said bore, said die means permitting properly formed articles to pass therethrough and capturing defective articles; and b. means for permitting said captured defective articles to be removed from said die means.
 7. The apparatus of claim 6, further including means for sensing the presence of captured dEfective article.
 8. The apparatus of claim 6, wherein said means for permitting said captured defective article to be removed includes: a. first and second plates forming said die member, a portion of said convergent-divergent passage being formed in said first member and the remaining portion of said convergent-divergent passage being formed in said second member; and b. clamping means for holding said first and second members together and permitting said first and second members to be disassembled to remove a captured defective article.
 9. The apparatus of Claim 7, wherein said means for sensing the presence of a captured defective article includes: a. a transparent portion of said conveying line located adjacent to the entrance end of said die means; b. means for sensing the presence of a stationary article in said transparent portion; and c. circuit means connected to said sensing means for deactivating and reactivating an article transmitter.
 10. The apparatus of claim 6, further including by-pass means in said die means for allowing the conveying fluid to by-pass said captured defective article.
 11. The apparatus of claim 10, wherein the said by-pass means includes the plurality of grooves extending radially outward from said convergent-divergent bore, the bottom surface of said grooves forming the outline of a cylinder which is slightly larger than the entrance and exit diameter of said convergent-divergent bore and which is concentric with the bore at any cross-section through said die member.
 12. The apparatus of claim 11, wherein said means for permitting said captured defective articles to be removed include: a. first and second plates forming said die member, a portion of said convergent-divergent bore being formed in said first member and the remaining portion of said convergent-divergent bore being formed in said second member; and b. clamping means for holding said first and second members together and permitting said first and second members to be disassembled to remove a captured defective article. 